Turntable for phonographs and sound recorders



Aug. 14,1945, v, L. ROBERTS 7 TURNTABLE FOR PHONOGRAPHS AND SOUNDRECORDERS Filed Nov. 27, 1941 a 22' 7R4 hi 1 52 7; jf

Patented Aug. 14, 1945 I 7 2,381,927 r TURNTABLEFOR PHONOGRAPHS AND rSOUND RECORDERS Vernon L. Roberts, Chicago, Ill., assignor of one r jhalf to Richard H. Wann, Detroit, Mich.

- Application November 27, 1941', Serial No. 420,725

My invention relates to turntables for phonographs and sound recorders,andhas to 'do more particularly with a turntable which is especiallycdesigned for home machines which are adapted for makingand playingsound records.

In the manufacture of commercial sound discs, it is customary toequip'the disc with an eccentric control groove communicating with theterminal portionof thespiral'sound' groove, this eccentric groovefunctioning to impart an in-and-out .movement .to thereproducing stylusand tone arm Said' movement actuates a stop mechanism, recordchanging'mechanismmr the like.

In the making of home records, it has heretofore not'been -consideredfeasible to apply to the record such .an eccentric groove and this hasresulted inconsiderable inconvenience to-the' user because of thenecessity of manual control following the playing of each home'recordingr I :In my copending application, SerialNo. 387,- f

800, filed April 10,1 1941,'noW Patent No. 2,309,276, granted. Jan; 26,11943, I have suggested a means of providing aneccentric groove'to arecord by a record may be rotated alternatively either on its truecenteror on an axis ofiset from the center of thedisc, resulting in aneccentric groove. 7

Anotherobject is to provide such an arrang e- 'ment which will be simplein construction; inex pensive to-' fabricate and, in. general, entirelysatisfactoryfor the purposes desired.

Referring now to the drawing forming a part of this specification andillustrating certain preferred embodiments-of.-my-invention 1 Fig, 1- isa top planview ofaturntable'constituting-one't-means of practicing myinvention; Fig. 2 is a diametrical sectional view taken substantiallyalong the line 2-2 of Fig.1;

Fig. -3 is a plan view showing'another'embodiment of my invention; 1Fig. 4 is an elevational View taken from a point substantiallyalong theline 44 of Fig. 3;

:Fig. 5' is a plan view of still another embodiment of my invention; and

i Fig. 6 is a perspective View of anelement of the embodiment shown inFig. 5; Referring first to the form shown in FigsJl and 2, the numeralIt] represents generally a'turntable mounted on a support I 2, thelatter being in turn rotatably connected to motor drive mechanism (notshown). The turntable ID is provided with a spring-pressed locking pinl5 which is adapted to seat in a recess in a record at a point near thecenter-thereof to prevent slippage between'the record and. turntable,and theturntable is also provided with a center threaded hole I 6receiving a locking spindle l8 for securing the record through itscenter aperture in axial alinement with. the turntable.

According to my invention, another threaded aperture 20 is provided inthe turntable at the same distance from the locking pin l5 as theaperture Hi. This aperture 20 is preferably disposed as close to thecenter aperture'lfi as possible, in order that'a'control groove ofsmallest diameter may be provided and thus permit production of a recordof maximum length.

Use of the turntable just described will be readily apparent. The blankrecord isfirst secured to.

the turntable with its center hole in registry with the turntable centerhole IS, the clamping element l8 being threaded into the hole -16 and'thelocking pin ['5 in registry with-the recess formed-for the purpose inmost standard records. The record is made by traversing the cuttingstylus in a spiral path from a point near the periphery of the record tosome point between the periphery and 'the center, in accordance withstandard practice.

After the sound groove has been completed, the record is removed fromits original position to a position with its center hole in registrywith the off-center threaded hole 20.

This operation, of course, may be done without removing the record fromthe turntable, since it may he slid thereon while being retained withits locking recess inengagement with the locking pin i'5;' The record isthen again secured by the clamping element It with its center hole inregistry with the 01f center hole 20 of the turntable.

The recording stylus is then replaced in the sound grooveat or adjacentthe inner terminus thereof and the turntable is again set in motion.Obvi'- 21, which, may, if desired, extend through the turntable andfunction as a record locking pin similarly to the pin 15 in Figs. .1 and2. The arm 25 carries a stud 30 adjacent its inner extremity, this studextending through a slot 32 passing through the center-of the turntable.This slot is preferably an arc having as a radius its distance'from pin21. The arm 25 extends beyond the periphery of the turntable to providea hamdle portion, as seen best in Fig. 3, and the marginal iiange 33 ofthe turntable may be provided with a pa1r of spaced slots 34, 34' snuglyreceiving the arm 25, an elongated slot 35 connecting the slots 34 and34'. The arm by its own resilience or otherwise may be firmly. retainedalternatively in one of the slots 34, 34'.

It will be seen that when the arm is fixed in the slot 34, the pin iscentrally disposed with reference to the turntable while, when the armis moved into the sot 34, the pinds off: center,

where it will function in the formation r an eccentric groove in arecord.

In the embodiment shown inFigs. 5 and 6, the

turntable IE1 is provided with a tapered socket 40, which extends fromthe center of the turn table to a point the'rebeyond. seated a similarlytapered plug 42 which carries, preferahl r integrally therewith, ,a stud45'. It will be seen that by reversingthe plug 421m the socket Mlthestud 5 may bepositioned either centrally of--the record or offcenter, so that it may hetused in the manner described above either forsaidaperture of the-disc,v means enablingsaid studi-to be adjusted froma position atthe center of. the turntable to a. position eccentricthereto, and meansapositively holding the stud at either position.against movement transversely of its axis.

2. A'turntablefor supporting a record disc which has a central aperture,'a driving stud cocentrically disposed in the turntable, and a secondstud upstanding from the turntable and engageab-le.- in said aperture ofthe disc, and means-enabling said stud to be adjusted from a position atthe center of the turntable to a posi- In this socket istion eccentricthereto, said second stud being disposedi-at the same distance from saiddriving stud in both positions.

3,..A turntable forv supporting a record disc which hasia centralaperture, a driving stud ecccntrically disposed'in the turntable, alever fulcrumed on the under side of thet'able at the axis of. saiddriving stud, the table having anopening in. its central portion" and asecond stud carried by said lever and upstanding through said openingfor engagementin the aperture of the disc, said opening in. the tablebeing dimensioned to accommodatethe stud at the center of the table andalso at a position eccentric thereto and the lever being movable aboutits axis to shift said I stud from one position to the other.

4. A turntable for supportinga record disc which has a central aperture,a driving stud eccentrically disposed in the turntable, a leverfulcrumed' on the under side of the table at the axis of said drivingstud, thetable having an opening in its central portion and a secondstud carried by said lever and upstanding through said open ing forengagement in the aperture of the disc,

saidopening in the table being dimensioned to accommodate the stud atthe center of the table and also at a position eccentric thereto and thelever being movable about. its axis to shift said stud from onepositionto the" other, together with means which locks the lever when the studis adjusted at either of said positions.

5. A turntable for supporting a record disc which has a centralaperture, said table having a recess formed at the f center of the tableand extending outwardly for a. limited distance, a

stud dimensioned to fit the aperture of the disc, and means supportingsaid stud in the recess of the table and upstanding from the latter,said supporting means being adjustable to position said stud eitheradjacent one end of the recess and at the center of the table oradjacent the EOithEIlT-EflldiOf the recess and in eccentric relation tothe table.

6;:A- turntable for' supporting a record disc which has a: :centralaperture, 2. driving stud eocentrically disposed in the turntable, saidtable havingrarecessformed at thecenter of the table and extendingoutwardly for a limited distance,

a second studdimensioned'to fit the aperture of the disc, meanssupporting said second stud in the recess of the table and upstandingfrom the-latter, said supporting means being adjustable-to position saidsecond stud either adjacent one-end-of the recess and at the center ofthe table or, adj acentthe other end ofv the recess and in eccentricrelation to the table, said second stud being: disposed at the samedistance from the dniving stud in both positions.

'7. A turntable for supporting a record disc which has acentralaperture, a threaded stud dimensioned to fit the aperture of the disc,the table having a threaded opening at its center to receive the studand a second threaded opening-for said stud at an eccentric position.

8. A turntable for supporting a record disc which has azcentralaperture, the table having arecess, a block fitted in saidrecess with astud upstanding from the block dimensioned to engage the aperture of thedisc, said block being adj-ustable in the recess with the stud disposedeither at the center of the table or in eccentric relation thereto.

9. A turntable for supporting a record disc which has a centralaperture, the table having a pair of recesses, one at the center of thetable and one in eccentric relation thereto, and a stud removably and.selectively engageable in either recess and dimensioned to'project abovethe surface of the table when so engaged and to fit the aperture ofthedisc.

10. A turntable for supporting a sound rec- 0rd, a-record positioningelement carried by said turntable-for positioning a record in definiterelations thereto, said turntable having means to supportand hold saidelement in alternative positionaoneof said positions being co-axial withsaid turntable and theother'position being eccentric. to said.turntable;

11. A turntable to support a record disc, and astudin upstandingrelation to said turntable to project upwardly into an aperture at thecen ter of the record disc, said turntable having space co-axialtherewith and space eccentric thereto, for accommodating said studselectively in co-axial and eccentric relation to said turntable.

VERNON L. ROBERTS.

